1. Field of the Invention
The present invention relates to a document reading apparatus typified by an automatic document feeder unit (ADF) or to an image forming apparatus including the ADF such as a copier or a laser beam printer.
2. Description of the Related Art
Conventionally, in such an image forming apparatus, a document conveyance path to a document reading unit of a document conveyance type and a recording material conveyance path in an image forming unit for a recording material are independent of each other. Specifically, for each of the document and the recording material, a paper feed unit, a guide member that constitutes a predetermined conveyance path, a plurality of conveyance rollers, a motor that drives the conveyance rollers, a paper discharge unit, or the like are independently provided. Thus, increases complexity of an entire mechanism of the image forming apparatus, cost, and a size of the apparatus. Therefore, for example, Japanese Patent Application Laid-Open No. 2006-232467 proposes that a document reading unit is provided in a duplex conveyance path of a recording material, and a document conveyance path and a recording material conveyance path are shared and used to simplify a conveyance mechanism and reduce cost and size thereof.
For example, Japanese Patent Application Laid-Open No. H10-129071 discloses a technique of reading an image printed on a document, preparing an overwriting image based on the image, and performing overwriting printing on the read document. A document conveyance path and a recording material conveyance path are shared and used to allow a document after reading to be used as it is as a recording material, thereby facilitating overwriting printing.
However, when the overwriting printing is performed, the conventional configuration does not consider a measure for a case where an image on a document to be read is deteriorated, and thus overwriting printing is performed with lines or letters in the document being hard to read. Reading and overwriting printing of a deteriorated image are repeated to cause more severe deterioration of the image, thereby providing a final print hard to recognize.
The present invention is achieved in view of such circumstances, and allows printing of an overwritten final print easy to recognize even when a read document is deteriorated.